BAD: Increases any axle wrap problems you may have now, IMO, a wrap-bar is required even if still SUA. Can cause minor geometry issues with driveshaft vibrations. Will require minor brake line adjustments, relocating shock mounts. Odd are you get to trim your wheelwells out a fair amount, requires lengthening the rear driveshaft.

GOOD: Provides added clearance at the tub for 35+ tires, longer wheelbase is better for hillclimbs, gives you a good excuse to find some 55/60 rear packs and swap them in.

proper axle shimming will eliminate vibration....http://www.4xshaft.com has nice tech pics so it makes sense. In short, the down face angle of the t-case output must match the up face angle of the pinion input.

No custom shaft required, just retube. Custom is no better than stock, unless you dump LOTS of money into some funky stuff.